Yahoo Mail has recently enabled a DMARC reject policy to protect users from increasing email spam that uses Yahoo users email addresses from other mail servers (you can read about it here
With the recent policy change, DMARC compliant systems will reject such emails.
To help assist our customers through this change, we have outlined the remediation in our case. You should follow the
applicable recommendations from those we have listed below:
1. If you are sending the email on behalf of a business:
a. then the customer is best served if they move to sending email from their own domain; OR
b. Use an address you control, which could be a dedicated address at your site. E.g. If you are "b2b.example" then "From: "Example Sender"<email@example.com>"; OR
c. Use a single address for different senders E.g. If you are "b2b.example" then you could do
i. "Reply-to: "Example Sender" <firstname.lastname@example.org>"; AND
ii. "From: "Example Sender" <email@example.com>"
2. If you are an ISP or an email provider and your users want to use Yahoo addresses; then
a. We can consider allowing customers to connect directly to Yahoo SMTP servers; OR
b. Contact Yahoo support at firstname.lastname@example.org to discuss authentication and configuration options.
For additional details, please click here
If you need any clarifications or further information on the above mentioned changes made by Yahoo, please feel free to reach out to